Helaian Penipuan JavaScript

王林
Lepaskan: 2024-08-08 03:41:12
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987 orang telah melayarinya

JavaScript Cheat Sheets

Hey everyone! I've got some great news for all you beginners learning JavaScript! A quick reference guide for JavaScript is now available! You can easily check important concepts, functions, and methods right away. For more details about the guide, check it out here.

What's in the Quick Reference Guide

Console

// => Hello world! console.log("Hello world!"); // => Hello CheatSheets.zip console.warn("hello %s", "CheatSheets.zip"); // Output error message to standard error console.error(new Error("Oops!"));
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Numbers

let amount = 6; let price = 4.99;
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Variables

let x = null; let name = "Tammy"; const found = false; // => Tammy, false, null console.log(name, found, x); var a; console.log(a); // => undefined
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Strings

let single = "Wheres my bandit hat?"; let double = "Wheres my bandit hat?"; // => 21 console.log(single.length);
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Arithmetic Operators

5 + 5 = 10 // Addition 10 - 5 = 5 // Subtraction 5 * 10 = 50 // Multiplication 10 / 5 = 2 // Division 10 % 5 = 0 // Modulus
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Comments

// This is a comment /* You need to change this setting before deployment. */
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Assignment Operators

let number = 100; // Both statements add 10 number = number + 10; number += 10; console.log(number); // => 120
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String Interpolation

let age = 7; // String concatenation "Tommy is " + age + " years old."; // String interpolation `Tommy is ${age} years old.`;
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Conditional Statements

const isMailSent = true; if (isMailSent) { console.log("Mail sent to recipient"); }
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Ternary Operator

var x = 1; // => true result = x == 1 ? true : false;
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Logical Operators

true || false; // true 10 > 5 || 10 > 20; // true false || false; // false 10 > 100 || 10 > 20; // false
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Comparison Operators

1 > 3; // false 3 > 1; // true 250 >= 250; // true 1 === 1; // true 1 === 2; // false 1 === "1"; // false
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Arrays

const fruits = ["apple", "orange", "banana"]; // Different data types const data = [1, "chicken", false];
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Objects

const apple = { color: "Green", price: { bulk: "$3/kg", smallQty: "$4/kg" }, }; console.log(apple.color); // => Green console.log(apple.price.bulk); // => $3/kg
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Classes

class Dog { constructor(name) { this._name = name; } introduce() { console.log("This is " + this._name + " !"); } // Static method static bark() { console.log("Woof!"); } } const myDog = new Dog("Buster"); myDog.introduce(); // Calling static method Dog.bark();
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Modules

// myMath.js // Default export export default function add(x, y) { return x + y; } // Named export export function subtract(x, y) { return x - y; } // Multiple exports function multiply(x, y) { return x * y; } function duplicate(x) { return x * 2; } export { multiply, duplicate };
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Asynchronous Processing

function helloWorld() { return new Promise((resolve) => { setTimeout(() => { resolve("Hello World!"); }, 2000); }); } async function msg() { const msg = await helloWorld(); console.log("Message:", msg); } msg(); // Message: Hello World! <-- after 2 seconds
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This quick reference guide covers a wide range of topics from the basics to more advanced JavaScript concepts. Be sure to download it here and make it a handy tool for your coding journey!

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